U.S. patent number 8,297,673 [Application Number 13/290,394] was granted by the patent office on 2012-10-30 for gripper with central support.
This patent grant is currently assigned to Norgren Automation Solutions, LLC. Invention is credited to Anthony Jenkins, James R. Kalb, Conrad Earl Waldorf.
United States Patent |
8,297,673 |
Waldorf , et al. |
October 30, 2012 |
Gripper with central support
Abstract
A gripper assembly including at least one gripper jaw and an
actuator head linked with the at least one gripper jaw. An actuator
selectively operates to move the actuator head between a plurality
of positions. A support is fixed relative to the actuator and
includes a guide slot that guides the actuator head. One of the
actuator head or the guide slot includes a channel and the other of
the actuator head or the guide slot includes a guide member
extending there from at least partially into the channel.
Inventors: |
Waldorf; Conrad Earl (Pinckney,
MI), Jenkins; Anthony (Clawson, MI), Kalb; James R.
(Petersburg, MI) |
Assignee: |
Norgren Automation Solutions,
LLC (Saline, MI)
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Family
ID: |
38477272 |
Appl.
No.: |
13/290,394 |
Filed: |
November 7, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120049553 A1 |
Mar 1, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12890033 |
Sep 24, 2010 |
8070202 |
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11786944 |
Nov 23, 2010 |
7837247 |
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60831531 |
Jul 18, 2006 |
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Current U.S.
Class: |
294/203;
294/116 |
Current CPC
Class: |
B25J
15/0226 (20130101); B25B 5/087 (20130101) |
Current International
Class: |
B25J
5/00 (20060101) |
Field of
Search: |
;294/115,116,198,202,203
;269/32,34 ;901/37 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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4236670 |
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May 1994 |
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DE |
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0747172 |
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Dec 1996 |
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EP |
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9212831 |
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Aug 1992 |
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WO |
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9815392 |
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Apr 1998 |
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WO |
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Other References
International Search Report and Written Opinion dated Dec. 13,
2007. cited by other .
International Preliminary Report on Patentability dated Nov. 4,
2008. cited by other.
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Primary Examiner: Kramer; Dean
Attorney, Agent or Firm: Young Basile Hanlon &
MacFarlane P.C.
Parent Case Text
REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser.
No. 12/890,033, now U.S. Pat. No. 8,070,202, filed on Sep. 24,
2010, which is a continuation of U.S. patent application Ser. No.
11/786,944, filed on Apr. 13, 2007, now U.S. Pat. No. 7,837,247,
which claims the benefit of U.S. Provisional Application No.
60/831,531, filed on Jul. 18, 2006.
Claims
The invention claimed is:
1. A gripper assembly, comprising: a first gripper jaw having a cam
slot; a second gripper jaw having a cam slot; an actuator; a cam
assembly that is operatively connected to the actuator, extends
laterally outward with respect to the actuator, and is engageable
with the cam slot of the first gripper jaw and the cam slot of the
second gripper jaw for moving the first gripper jaw and the second
gripper jaw in response to movement of the actuator; and a central
support that is fixed relative to the actuator and is positioned
between the first gripper jaw and the second gripper jaw, such that
the first gripper jaw is adjacent to a first exterior surface of
the central support, and the second gripper jaw is adjacent to a
second exterior surface of the central support, the central support
including a hollow central portion that receives at least a portion
of the cam assembly, wherein the central support defines a first
guide feature that is positioned between the first gripper jaw and
the second gripper jaw, the cam assembly defines a second guide
feature, and engagement of the first guide feature with the second
guide feature limits lateral movement of the cam assembly with
respect to the central support during movement of the actuator.
2. The gripper assembly of claim 1, wherein one of the first guide
feature or the second guide feature includes an aperture, and the
other of the first guide feature or the second guide feature
includes a guide structure that extends at least partially into the
aperture.
3. The gripper assembly of claim 2, wherein the aperture includes a
closed bottom surface that is defined by the central support.
4. The gripper assembly of claim 2, wherein the aperture extends
through the central support.
5. The gripper assembly of claim 2, wherein the aperture is a
laterally open slot.
6. The gripper assembly of claim 1, wherein the cam assembly
includes an actuator head, and the second guide feature is a
portion of the actuator head.
7. The gripper assembly of claim 1, wherein the cam assembly
includes at least one cam pin that is disposed in the cam slot of
at least one of the first gripper jaw or the second gripper
jaw.
8. The gripper assembly of claim 7, wherein the cam assembly
includes a roller that is disposed on the at least one cam pin, is
disposed in the cam slot of at least one of the first gripper jaw
or the second gripper jaw, and is engageable therewith.
9. The gripper assembly of claim 1, wherein the cam assembly
includes a first cam pin that is disposed in the cam slot of the
first gripper jaw and a second cam pin that is disposed in the cam
slot of the second gripper jaw.
10. The gripper assembly of claim 1, wherein the first guide
feature includes a slot that is defined by the central support, the
slot extending from the hollow central portion of the central
support to the first exterior surface of the central support.
11. The gripper assembly of claim 1, wherein the actuator includes
a piston rod that is at least partially disposed within the hollow
central portion of the central support.
12. A gripper assembly, comprising: a first gripper jaw having a
cam slot; a second gripper jaw having a cam slot; an actuator; a
cam assembly that is operatively connected to the actuator and is
engageable with the cam slot of the first gripper jaw and the cam
slot of the second gripper jaw for moving the first gripper jaw and
the second gripper jaw in response to movement of the actuator; and
a monolithic central support that is fixed relative to the actuator
and is positioned between the first gripper jaw and the second
gripper jaw, the central support including a hollow central portion
that receives at least a portion of the cam assembly, wherein the
central support defines a first pair of guide features, the cam
assembly defines a second pair of guide features, and engagement of
the first pair of guide features with the second pair of guide
features linearly guides the cam assembly with respect to the
central support during movement of the actuator.
13. The gripper assembly of claim 12, wherein each guide feature of
the first pair of guide features includes an opening and each guide
feature of the second pair of guide features includes a guide
structure that extends at least partially into a respective one of
the openings.
14. The gripper assembly of claim 12, wherein each guide feature of
the second pair of guide features includes an opening and each
guide feature of the first pair of guide features includes a guide
structure that extends at least partially into a respective one of
the openings.
15. The gripper assembly of claim 14, each guide feature of the
first pair of guide features includes a closed-bottom channel.
16. The gripper assembly of claim 14, each guide feature of the
first pair of guide features includes a laterally open slot.
17. The gripper assembly of claim 12, wherein the cam assembly
includes an actuator head and at least one cam pin that is disposed
in the cam slot of at least one of the first gripper jaw or the
second gripper jaw.
18. The gripper assembly of claim 17, wherein the cam assembly
includes a roller that is disposed on the at least one cam pin, is
disposed in the cam slot of at least one of the first gripper jaw
or the second gripper jaw, and is engageable therewith.
19. The gripper assembly of claim 12, wherein the cam assembly
includes a first cam pin that is disposed in the cam slot of the
first gripper jaw and a second cam pin that is disposed in the cam
slot of the second gripper jaw.
20. A gripper assembly, comprising: a first gripper jaw having a
cam slot; a second gripper jaw having a cam slot; an actuator
including a piston rod; a cam assembly that is operatively
connected to the piston rod of the actuator and is engageable with
the cam slot of the first gripper jaw and the cam slot of the
second gripper jaw for moving the first gripper jaw and the second
gripper jaw in response to movement of the actuator; and a central
support that is fixed relative to the actuator and is positioned
between the first gripper jaw and the second gripper jaw, the
support including a hollow central portion that receives at least a
portion of the cam assembly and the piston rod of the actuator,
wherein the central support defines a first pair of guide features,
the cam assembly defines a second pair of guide features, the first
pair of guide features and the second pair of guide features are
positioned between the first gripper jaw and the second gripper
jaw, and engagement of the first pair of guide features with the
second pair of guide features linearly guides the cam assembly with
respect to the central support during movement of the actuator.
Description
BACKGROUND OF THE INVENTION
This invention generally relates to automated handling equipment.
More particularly, this invention relates to an actuated gripper
device having a central support that guides movement of the
actuator and supports at least one gripper jaw.
Automated handling equipment is typically employed in industrial
settings for transferring work pieces between work stations.
Typically, the equipment includes an actuated gripper that clamps
the work pieces while moving them between the stations.
One type of conventional gripper includes an actuator that linearly
reciprocates a piston. The piston is coupled to a cam pin that
extends outward in opposite directions from the end of the piston.
The respective opposing ends of the cam pin are received through
cam slots of two opposed gripper jaws, which are received between
two sidewalls that extend from the actuator. Each sidewall includes
a pivot pin that extends between the sidewalls and through the
gripper jaws to pivotally support the jaws from the sidewalls. A
cover is usually secured to the outside of each sidewall with
multiple fasteners to prevent the pivot pin from sliding out from
between the side walls during use. Typically, the sidewalls also
include guide slots that guide the ends of the cam pin as the cam
pin slides along the cam slots of the jaws to pivot the jaws about
the pivot pins between open and closed jaw positions.
The jaws of typical grippers are removable and replaceable with
different jaws to accommodate work pieces of varying shapes and
sizes. For example, jaws having different cam slot lengths and
shapes (i.e., slot angles) may be substituted to change the size of
the opening between the jaws. One drawback of conventional grippers
is that removing the jaws is rather complex and time consuming. For
example, in the conventional gripper described above, the multiple
fasteners and the pivot pin must be removed. Each jaw must then be
disassembled from the cam pin, which may be tedious because of the
confined space between the side walls. Thus, the conventional
gripper construction requires assembly and disassembly of a
relatively large number of components within a tight space to
replace the jaws. Accordingly, there is a need for a gripper
construction that provides more convenient jaw replacement.
SUMMARY OF THE INVENTION
An example gripper assembly for providing easy jaw replacement
includes at least one gripper jaw and an actuator head linked with
the at least one gripper jaw. An actuator selectively moves the
actuator head between a plurality of positions to move the gripper
jaw. A support is fixed relative to the actuator and includes a
guide slot that receives the actuator head. One of the actuator
head or the guide slot includes a channel and the other of the
actuator head or the guide slot includes a guide member extending
there from at least partially into the channel.
In another aspect, the support of an example gripper assembly
includes at least one bearing surface that pivotally supports at
least one gripper jaw.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates example gripper assemblies for moving work
pieces between work stations.
FIG. 2 illustrates a partially exploded view of an example gripper
assembly of FIG. 1.
FIG. 3 illustrates a perspective view of selected portions of the
example gripper assembly of FIG. 2.
FIG. 4 illustrates a cross-sectional view of selected portions of
the example gripper assembly of FIG. 2.
FIG. 5 illustrates a perspective view of selected portions of the
example gripper assembly of FIG. 2.
FIG. 6 illustrates another embodiment of a gripper assembly.
FIG. 7 illustrates a portion of a modified gripper jaw.
FIG. 8 illustrates a portion of another modified gripper jaw.
FIG. 9 illustrates another example gripper assembly.
FIG. 10 illustrates an isolated view of a support of the gripper
assembly of FIG. 9.
FIG. 11 illustrates a partial view of the gripper assembly of FIG.
9 without the gripper jaws.
FIG. 12 illustrates another partial view of the gripper assembly of
FIG. 9 without the gripper jaws.
FIG. 13 illustrates the gripper assembly of FIG. 9 with an optional
cover.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 schematically illustrates selected portions of several
gripper assemblies 10 used in an example industrial setting to grip
and move a work piece 12 (shown schematically). The gripper
assemblies 10 may be used in a variety of different configurations
from that shown. In this example, the gripper assemblies 10 are
coupled to extended arms 14, which are each secured to a rail 16.
An adapter arm 18 is secured to the rail 16. An automated machine
20, such as a robot, moves the adapter arm 18, the extended arms
14, and the gripper assemblies 10 to desired positions to retrieve
and deposit the work pieces 12, such as between work stations.
FIGS. 2-5 illustrate various views of selected portions of an
example gripper assembly 10. FIG. 2 is a partially exploded view of
the gripper assembly 10. FIG. 3 is a partial view of the gripper
assembly 10 without one of the jaws. FIG. 4 is a sectioned view,
and FIG. 5 is a partial view of the gripper assembly 10 without one
of the jaws or a central support. With reference to these figures,
the gripper assembly 10 includes an actuator 30, such as a
pneumatic or hydraulic actuator, that actuates a piston rod 31 in a
known manner to selectively open or close the gripper jaws 32a and
32b. For example, the actuator 30 includes a housing 34 that
contains a piston within a bore (not shown).
The gripper assembly 10 includes a support 36 having a flange 38
and a support section 40 that extends from the flange 38 generally
parallel to the piston rod 31. In this example, four fasteners 42
are received through the flange 38 and into the housing 34 to
secure the support 36 and actuator 30 together.
The support 36 includes a hollow central portion 44 (i.e., a guide
slot), cam slots 46 that open laterally relative to the length of
the hollow central portion 44, and pivot bosses 48 (one shown). The
piston rod 31 extends within the hollow central portion 44, which
functions as a guide slot for guiding movement of the piston rod
31.
In this example, the support 36, including the pivot bosses 48, is
an integral, monolithic piece, which may be formed from a single
type of material, for example. The support 36 may be machined from
a preformed metal blank, cast, or formed in another known manner to
produce the illustrated shape or other desired shape. Given this
description, one of ordinary skill in the art will recognize other
methods of making the support 36 to suit their particular
needs.
A distal end (relative to the actuator 30) of the piston rod 31 is
coupled with a cam head 50. Cam pins 52a and 52b are coupled with
the cam head 50 and extend outward in opposite lateral directions
from the cam head 50. In the disclosed example, two cam pins 52a
and 52b are offset from each other such that the cam pins 52a and
52b are non-coaxial. Alternatively, a single cam pin extending in
both lateral directions from the cam head 50 or two coaxial cam
pins may be used.
Optionally, a roller 54 is received on each of the cam pins 52a and
52b. The cam pins 52a and 52b and rollers 54 are received into cam
slots 56 within each of the jaws 32a and 32b. The rollers 54
facilitate movement of the cam pins 52a and 52b through the cam
slots 56.
The jaws 32a and 32b are received onto the respective pivot bosses
48. That is, the pivot bosses 48 are received at least partially
into respective openings 59 through each of the jaws 32a and 32b. A
fastener 58 is received though the opening 59 through each of the
jaws 32a and 32b and into the respective pivot bosses 48 to prevent
the jaws 32a and 32b from sliding off of the pivot bosses 48.
In the illustrated example, the fasteners 58 are threaded and mate
with threads within the pivot bosses 48. The fasteners 58 secure
the jaws 32a and 32b to the support 36. In this example, there is
some play between the pivot bosses 48 and the openings 59 such that
the jaws 32a and 32b can pivot about the respective pivot bosses
48. That is, the pivot bosses 48 provide a bearing surface 61 for
rotation of the jaws 32a and 32b.
The fasteners 58 also secure a cover 60 (FIG. 2) over each of the
jaws 32a and 32b, which retains the roller 54 within the gripper
assembly 10 if the rollers 54 are not secured laterally on the cam
pins 52a and 52b. Alternatively, the pivot bosses 48 extend
entirely through each of the openings 59, and the fasteners 58 are
c-clips (not shown) that secure to the respective ends of the pivot
bosses 48 to pivotally secure the jaws 32a and 32b on the support
36.
In this example, the flange 38 of the support 36 also includes a
slot 39a in the shape of a dovetail, for example, that receives a
tab 41a on the cover 60. Another slot 39b supports another tab 41b
on the cover 60. The tabs 41a and 41b interlock with the slots 39a
and 39b to hold the cover on the gripper assembly 10 such that the
cover openings 43 align with respective pivot bosses 48 for
receiving the fasteners 58.
In another embodiment shown in FIG. 6, the gripper assembly 10 does
not include the covers 60 and instead utilizes keyed washers 63
(one shown) that fit onto respective pivot bosses 48' to hold the
jaws 32a and 32b on the gripper assembly 10. Each pivot boss 48'
includes flat sides 65a and 65b that correspond to flat sides 67a
and 67b of the keyed washer 63. The flat sides 65a, 65b, 67a, 67b
prevent the keyed washer 63 from rotating once received onto the
pivot boss 48'.
In one example, the covers 60 may not be desired if the rollers 54
are laterally secured to the cam pins 52a and 52b. For example, the
rollers 54 and respective cam pins 52a and 52b may include a
tongue-and-groove connection that prevents the rollers 54 from
sliding laterally on the cam pins 52a and 52b. Other types of
connections may also be used to secure the rollers 54 on the cam
pins 52a and 52b.
In another example, the covers 60 may not be needed to retain the
rollers 54 on the respective cam pins 52a, 52b if modified versions
of the gripper jaws 32a and 32b are used. FIG. 7 shows one example
of a portion of another version of a gripper jaw 32' that is
similar to the jaws 32a and 32b. In this example, the gripper jaw
32' includes a cam slot 56' that extends partially through the
thickness of the jaw 32', rather than entirely through a cam slot
56 of the jaws 32a and 32b, such that an inner wall 69 retains the
roller 54 on the cam pin 52a.
FIG. 8 shows another example of a portion of another version of a
gripper jaw 32'' that is similar to the jaws 32a and 32b. In this
example, the jaw 32'' includes a stepped cam slot 56'' that narrows
in a step-wise manner through the thickness of the jaw 32''. The
stepped shape allows the jaw 32'' to retain the roller 54 and
allows the end 71 of the cam pin 52a or 52b to extend entirely
through the jaw 32'' for the purpose of, for example, sensing
movement of the jaw 32'' via movement of the cam pin 52a or
52b.
In operation, the actuator 30 of the above example gripper
assemblies 10 selectively reciprocates the piston rod 31 to move
the cam head 50 and hence the cam pins 52a and 52b. The cam slots
46 in the support 36 linearly guide the cam pins 52a and 52b as the
cam pins 52a and 52b and respective rollers 54 translate through
the cam slots 56 of the jaws 32a and 32b (alternatively the slots
56' or 56'' of the jaws 32' or 32''). The movement of the cam pins
52a and 52b and rollers 54 through the cam slots 56 of the jaws 32a
and 32b causes the jaws 32a and 32b to pivot on the bearing
surfaces 61 about the respective pivot bosses 48 between open and
closed positions.
In the disclosed example, the construction of the gripper assembly
10 provides convenient replacement of the jaws 32a and 32b with
different jaws. To remove the jaws 32a and 32b, the fasteners 58
are removed. This allows the jaws 32a and 32b to slide off of the
cam pins 52a and 52b and rollers 54, and replacement jaws can then
be slid onto the cam pins 52a and 52b and rollers 54. If covers 60
are used, removal of the fasteners 58 also allows the covers 60 to
slide out from the slots 39a and 39b to access the jaws 32a and
32b.
It is the construction of the gripper assembly 10 that provides
such easy replacement of the jaws 32a and 32b. In the disclosed
example, the jaws 32a and 32b are supported by the pivot bosses 48
on the outside of the support 36 rather than between sidewall
supports as in previously known gripper assemblies. Thus, the pivot
bosses 48 provide a dual function of allowing the jaws 32a and 32b
to pivot and securing the jaws 32a and 32b to the support 36. This
allows the jaws 32a and 32b to be removed with the removal of fewer
components than previous gripper assemblies and provides direct
access to the jaws 32a and 32b rather than trapping the jaws
between sidewalls as in previous gripper assemblies.
FIG. 9 illustrates another embodiment of a gripper assembly 210
that is similar to the gripper assembly 10 except that the gripper
assembly 210 includes modified versions of a support 236 and a cam
head 250. In this example, components that are substantially
similar to the embodiments shown in FIGS. 2-5 are represented with
like numerals. FIG. 10 illustrates an isolated view of the support
236. In this example, the support 236 includes a hollow central
portion 244 that is laterally open but does not include the cam
slots 46 of the previous example gripper assembly 10.
The hollow central portion 244 extends from a mounting flange 238
to a curved end 201. The hollow central portion 244 includes guide
channels 203 and 205 that extend at least part of the distance
between the mounting flange 238 and curved end 201. In this
example, the guide channels 203 and 205 are of a non-uniform depth
such that the ends of the guide channels 203 and 205 gradually
become shallower in depth near the curved end 201. It is to be
understood that other example supports may include only a single
guide channel, and the channel or channels may also be of uniform
depth.
The support 236 also includes pivot bosses 248 having outer bearing
surfaces 261 for pivotally supporting jaws 32a and 32b. In this
example, the pivot bosses 248 and the support 236 form an integral,
monolithic piece. For example, the support 236 may be machined from
a preformed metal blank, cast, or formed in another known manner to
produce the illustrated shape or other desired shape.
The mounting flange 238 includes a first surface 211a and a second
surface 211b that is raised relative to the first surface 211a. The
raised second surface 211b functions as a locator to mount the
support 236 in a desired orientation onto a corresponding recessed
portion of the actuator 30.
The support 236 also includes a head 221 (i.e., a collision
surface) that may act to stop work pieces inserted between the jaws
32a and 32b, for example. In this example, the head 221 spans
across a distance 223 (FIG. 11) that is greater than a width 225 of
the hollow central portion 244. That is, the head 221 is larger
than at least the central portion of the support 236.
Referring to FIG. 11 (cam head 250 retracted) and FIG. 12 (cam head
250 extended), the guide channels 203 and 205 receive corresponding
guide members 207 and 209 formed on the cam head 250.
Alternatively, the guide channels 203 and 205 may be located on the
support 236. The guide members 207 and 209 interlock with the guide
channels 203 and 205 to linearly guide the cam head 250 as the
piston rod 31 reciprocates. That is, the guide channels 203 and 205
and the guide members 207 and 209 limit lateral movement of the cam
head 250 during reciprocation.
The cam head 250 includes a curved surface 231 that faces in a
direction generally outward from the actuator 30 and an opposing
surface 233 facing into a direction generally toward the actuator
30. In the illustrated example, the curved surface 231 has a
curvature that corresponds to a curvature of the curved end 201 of
the support 236. The combination of the curved surface 231 and the
curved end 201 with the gradually shallowing guide channels 203 and
205 reduces the length of the gripper assembly 210, which would
otherwise be longer if squared ends were used.
Optionally, as shown in FIG. 13, the gripper assembly 210 also
includes a cover 60' similar to the cover 60 in the previous
examples except that the cover 60' includes pivot tabs 241a and
241b that are slidably received into corresponding slots 239a and
239b of the support 236. The pivot tabs 241a and 241b allow
pivoting of the covers 60' about an axis B when the fasteners 58
are removed to provide access to the jaws 32a and 32b. That is, by
pivoting one of the covers 60' outward from the gripper assembly
210, the jaw 32a is free to slide off of the pivot boss 248 for
replacement. Likewise, the other jaw 32b can be removed and
replaced by pivoting the other cover 60'.
Although a combination of features is shown in the illustrated
examples, not all of them need to be combined to realize the
benefits of various embodiments of this disclosure. In other words,
a system designed according to an embodiment of this disclosure
will not necessarily include all of the features shown in any one
of the Figures or all of the portions schematically shown in the
Figures. Moreover, selected features of one example embodiment may
be combined with selected features of other example
embodiments.
The preceding description is exemplary rather than limiting in
nature. Variations and modifications to the disclosed examples may
become apparent to those skilled in the art that do not necessarily
depart from the essence of this disclosure. The scope of legal
protection given to this disclosure can only be determined by
studying the following claims.
* * * * *